TV Box H96 Max Plus 4GB/64Gb - movie streaming issue

[kapusta_z_grochem]

In 2018 I bought TV Box H96 Max Plus 4GB/64Gb Ram with Rockchip RK3328 processor. It was unused for a year and now I've connected it again. I reset and see a lot of artifacts on youtube, netflix and hbo. My wifi speed is 300mb, this device sees 60mb. I'm wondering what the problem might be? Even if I switch the quality to 480p t, green rectangles still appear. Any ideas how to fix it ? This video shows my problem https://www.youtube.com/watch?v=3fQaZYYu2nA